Conventionally, in a surgery such as a cataract surgery, a treatment has been performed in which an incision is provided in an ocular tissue such as a cornea (sclera) and an anterior capsule portion in the eyeball, an intracapsular crystalline lens is extracted and removed via the incision, and thereafter, an intraocular lens substituting the crystalline lens is inserted into the eye and disposed in the capsule from the incision.
Especially, in recent years, when inserting the intraocular lens into the eyeball from the incision, in many cases, an insertion device as illustrated below has been used. That is, a leading end opening of an insertion tube provided at a leading end portion of a device main body is inserted into the eyeball through the incision, and the intraocular lens is extruded from the leading end opening of the insertion tube by a rod-shaped plunger in the state of being slightly deformed in the device main body, thereby inserting the intraocular lens into the eyeball. By using such an insertion device, since it is possible to simply insert the intraocular lens into the eyeball by the use of the incision formed for extraction and removal of the crystalline lens, it is possible to simplify the surgery, and it is possible to suppress an occurrence of astigmatism and an occurrence of infectious disease after surgery.
Incidentally, in the insertion operation of the intraocular lens, when releasing the intraocular lens into the eyeball from the leading end opening of the insertion tube of the insertion device, in some cases, it has been difficult to stabilize the posture of the intraocular lens. That is, in some cases, since the intraocular lens may rotate (for example, forward roll) when being released from the leading end opening of the insertion tube and cannot be released while keeping a desired posture within the eyeball, the burden of posture adjustment of the intraocular lens within the eyeball after releasing the intraocular lens has increased.
Also, when releasing the intraocular lens from the leading end opening of the insertion tube, in some cases, the lens has been interposed between an inner wall of the insertion tube and a plunger, and the smooth release of the intraocular lens has been disturbed.